Tubular parabolic roof structure



' (No Model.)

1?. SGHMEMANN.

TUBULAR PARABOLIC ROOF STRUCTURE.

Patented July 22, 1890.

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UNITED Sterne Parent Prion.

TUBULAR PARABOLIC R00? STRUCTURE.

SPECIFICATION forming part of Letters Patent No. 432,771, dated July 22,1890. Application filedDecemher 1d, 1889- Serial No. 333,815. (Nomodel.)

To all whom it may concern.-

Be it known that I, FRIEDRICH SCHMEMANN, of the city of Philadelphia andState of Pennsylvania, have invented a certain new and usefulImprovement in Tubular Parabolic Roof Structures; and I do herebydeclare the following to be a full, clear, and exact descriptionthereof, reference being had to the accompanying drawings, formingpartof this specification.

My invention has relation to roof struetures; and it consists inreversed parabolic tubular trusses, as hereinafter particularly setforth and described.

The object of my invention is to produce a light and strong roofstructure, doing away with the necessity of a horizontal lower chord,and thus giving a clearance of roof-space, and being especially adaptedto long spans.

In the accompanying drawings similar letters of reference refer tosimilar parts throughout.

Figure 1 is an end or cross-sectional view of my improved reversedparabolic roof-truss, showing its bearing on the side walls or posts andthe shoe-fittings connecting the various parts. Fig. 2 is the lower orabutment shoecasting, into which the lower ends of the up per and lowerchords are fitted and connected. Fig. 3 is a cross-sectional view of theupper or apex casting on the line 00 o: of Fig. at, into which the upperends of the upper and lower chords are fitted and connected, and whichcasting connects together the trusses of each side of the roofstructure. Fig. 4 is a plan view of the casting shown in Fig. 3. Fig. 5is a plan View of the roof structure, showing the purlins in connectionwith the upper chords.

The upper chord A forms in its lower part a common parabola and in itsupper part a tangent thereto. The lower chord B forms in its upper parta common parabola and in its lower part a tangent thereto. These upperand lower chords A B are connected at their lower ends by theshoe-castings C O, which is provided on the top with a screw-tap t toreceive the pipe of the upper chord and in its lower part with acylindrical hole, into which the lower end of the lower chord B isloosely fitted. This lower end of the chord 15 the loclcnuts 3 turn.

is provided with a long screw-thread, and is secured into theshoe-casting C by means of the lock-nuts n n.

D D represent the upper or apex casting, into which the upper ends ofthe upper and lower chords A and B are respectively secured. The upperends of the two chords fit loosely into cylindrical holes providedtherefor in the castings D D and are secured thereto by lock-nuts s,which are screwed upon a long screw-thread provided on the upper ends ofthe said chords A I The upper ends of the two chords of the parabolictrusses being thus connected and secured by the castings D D,respectively, the two trusses are connected and secured together bymeans of two metal plates Z Z, the one on the top and the other on thebottom of the castings D D, through which the upper ends of the lowerchords B pass, respectively, and upon which The two castings D D thuspractically form one, and the double parabolic trusses of the respectivesides of the structure are thus securely and firmly united.

The upper and lower chords A B of the trusses are connected together intheir intermediate parts by means of the pipe-postsi and thescrew-threaded sleeve-fittings 0,which are of ordinary construction. Ashort horizontal pipe-connection c is preferably employed, as shown inFig. 1, connecting the parabolas of the lower chords B by means of thecastings d, in order to give additional strength and steadiness to thestructure.

The upper chords of the trusses are connected by the purlins p laidacross and on top of the said upper chords A and at right anglesthereto. These are of ordinary construction, either of wood or of iron,and are secured to the upper chords by vertical bolts running throughthe p urlin p and the chord A. When wooden purlins are employed, thewooden sheeting or covering is nailed on top directly thereto. "Whenmetal purlins are used, cross-braces run from the top of one metalpurlin to the other at right angles to the purlin and parallel with theupper chord A. Upon this superstructure the sheeting or slating issecured by hooks or by other suitable means.

The number of double parabolic trusses employed, stretching from wall towall, is regulated according to the strength desired, at, however, usualintervals. The strains produced on the lower parabolic chord have aninclined inward direction which will be transmitted in a verticaldirection to the central top casting D D and in an inclined inwarddirection to the shoe-casting O O. The upper chord transmits the load orstrain directly vertically through the shoe-castin g C C to the wall Wand to the top castings in an inclined direction.

This truss is preferably constructed of wrought tubular iron or steelpipe, welded or riveted, and joined together by ordinary screw-threadedsleeve-sockets.

This double reversed parabolic truss is also especially adapted forcupolas, giving to the same a graceful appearance, combined withrigidity and lightness of construction.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

1. In a roof structure, a truss having a tu bular upper chord providedwith a parabola at its lower end and a tangent thereto, in combinationwith a lower chord and pipeposts connecting the same, substantially ashereinbefore set forth and described.

2. In a roof structure, a truss having an upper parabolic chord, incombination with a lower chord having a parabola tending inward andupward at its upper end and a tangent thereto at its lower end and postsconnecting the said upper and lower chords, substantially ashereinbefore set forth and described.

3. A truss containing a tubular parabolic upper chord, in combinationwith a reversed tubular parabolic lower chord, pipe-posts connectingsaid upper and lower chords and lit tings connected thereto by means ofscrewthreads and slipped loosely over the chords, substantially ashereinbefore set forth and described.

4. A truss containing an upper parabolic .tubular chord and a lowerreversed parabolic castings connecting the chords, substantially ashereinbefore set forth and described.

6. A truss having an upper tubular parabolic chord and a lower reversedtubular parabolic chord, in combination with pipeposts connecting thesame by means of fittings, lower shoeecastings and upper or apexcastings into which the upper and lower chords are respectively fittedand plates connecting the upper castings of the two trusses,substantially as hereinbefore set forth and described.

7. A truss having an upper tubular parabolic chord A and a lowerreversed tubular parabolic chord B, in combination with pipeposts t,connecting the upper and lower chords A B, the shoe-fittings G G, theupper castings D D, plates Z Z, connecting the upper castings D D, theshort horizontal pipe-connection 0, connecting the parabolas of thelower chords B, and the superstructure and purlins p, substantially ashereinbefore set forth and described.

8. A truss having an upper tubular parabolic chord A and a reversedtubular parabolic chord B, in combination with pipe-posts connecting theupper and lower chords by suitable fittings, sl1oe-castings G 0,provided with a tap 5, into which the lower end of the upper chord isfitted, and a cylindrical hole into which the lower end of the lowerchord is loosely fitted and secured thereto by means of the lock-nuts nat, upper or apex castings D D, provided with two cylindrical'holes, re-

spectively, into which the upper ends of the upper and lower chords areloosely fitted and secured therein by means of lock-nuts s s,

connecting-plates connecting together the two castings D D,substantially as hereinbefore set forth and described.

In witness whereof I have hereunto set my handthis 3d day of December A.D. 1889;

FRIEDRICH SOHME-M'ANN.

